what is this thing I hear about ketchup and patina?

[sogflash]

every now and then I see something about putting ketchup or something else acidic on the blade to develop patina.

what is it for? can it be done on any kind of blade steel?

 

[Rockywolf]

I've used mustard, apples, pickle juice, to force a patina. It keeps rust from forming on a carbon blade.

 

[CWL]

I've used mustard, apples, pickle juice, to force a patina. It keeps rust from forming on a carbon blade.

Actually patina is a form of rust. It helps to resist formation of red rust on a knife, but don't count on it as your only means of corrosion resistance.

Most people who force patinas on their carbon knives are doing it for cosmetic reasons.

 

[sogflash]

does it only work on carbon steel? and why does patina form, and not iron oxide?

 

[rickc71]

I forced a patina years ago on my Ontario Spec Plus Marine SP1.I did it because after batoning wood with it for years,the black factory coating was completely worn off on most of the blade.Mustard works,as does vinegar and just about anything naturally acidic.Still need to keep it oiled,i like mineral oil as this will not contaminate food prep like gun oil.Since then I've done many 1095 and other high carbon steel blades in a forced patina.The bonus is that it looks cool/old and you can vary the design to suit your tastes.Very easy personalizing mod for a high carbon blade.Here's some pics
Luke Smith Custom with spot pattern mustard patina

ESEE Izula with striped pattern mustard patina

My old SP1 with vinegar random pattern forced patina

 

[RevDevil]

does it only work on carbon steel? and why does patina form, and not iron oxide?

A little independant research on the forums and google should provide you with an abundance of answers on this aspect.

 

[rivertamer]

Stripped my BK7..... Used Sriracha hot sauce to lay down the tiger stripes.... Works great.

 

[Obsessed with Edges]

does it only work on carbon steel? and why does patina form, and not iron oxide?

Patina ordinarily will only form on carbon steel, i.e. non-stainless steel ('stainless steel' usually refers to steel with chromium content of at least 12% or so; most 'carbon steel' for knives is well below that).

Patina on steel IS a form of iron oxide (there are several chemical forms), formed by a reaction between iron and oxygen.
http://en.wikipedia.org/wiki/Iron_oxide

Red rust is also a different form (chemically) of iron oxide, formed between iron and oxygen, in the presence of water or other moisture in the air.
http://en.wikipedia.org/wiki/Rust

In stainless steel, a portion of the extra chromium content will react with oxygen in the air, to form a very thin, essentially transparent layer of chromium oxide on the surface of the steel. That layer is very resistant to any further reaction with oxygen or moisture, which is why stainless steels are less likely to rust (or patina).

 

[eyeeatingfish]

I tried making a patina once and it came out but my problem was it seemed to wash away.

 

[getridone]

Anybody done a urine patina?? I had a bucket of urine ready to go any my wife yelled at me. I found that boiled vinegar gives a very dark patina, and seems to not have worn off very much.

 

[richard j]

Stripped my BK7..... Used Sriracha hot sauce to lay down the tiger stripes.... Works great.

i'm suprised it didnt melt your blade . that is some hot sauce. a bar i used to go to put that stuff in drinks. only a few people that came in would use it on food.

did you do a vinegar etch after the hot sauce?

 

[Long.Rider]

i'm suprised it didnt melt your blade . that is some hot sauce. a bar i used to go to put that stuff in drinks. only a few people that came in would use it on food.
did you do a vinegar etch after the hot sauce?

I just had some on my egg salad sandwich. You white folks are funny. How do you all live without some spice? That stuff is great one everything. Try it on scrambled eggs

 

[richard j]

years ago when my dad would eat hot sauce like that, he would say he would have to go use the bathroom in the creek to keep from setting the woods on fire

 

[Chipped Karambit]

Anybody done a urine patina?? I had a bucket of urine ready to go any my wife yelled at me. I found that boiled vinegar gives a very dark patina, and seems to not have worn off very much.

And the award for most awkward post of the year goes too!!!!!!! lol